This invention relates to the field of optical amplifiers and more specifically to the field of semiconductor optical amplifiers.
Because optical communications systems are being designed to transmit at several different wavelengths, there now exists a need for semiconductor optical amplifiers operating over a wide range of wavelengths. Since semiconductor optical amplifiers are compact, light in weight and are easily produced on a mass production scale, semiconductor amplifiers will play an important role in both optical communications and optical information processing systems.
Generally, a typical optical communications system may utilize several different wavelengths in order to transmit plural channels over a single common optical fiber. Amplifiers are periodically required along the optical transmission path to amplify the signals whose amplitudes have been attenuated due to transmission losses. Accordingly a broadband optical amplifier structure capable of amplifying plural channels at different wavelengths is required. In alternate situations where amplification of only one of the channels and filtering of the other channels is required, a wavelength selective amplifier which is tunable over a broadband range of wavelengths is necessary.